HLPC analytical procedures using anion exchange and anion exclusion chromatography with UV-absorption detection were developed to determine the composition of isolated tRNA from normal and induced-hepatoma monkey livers, the urinary excretion levels of tRNA degradation products, and the methylating ability of indiviual tRNA methyltransferases. Only minor variations in the tRNA base composition of the normal and hepatoma tRNA's were detected. However, increased urinary excretion of pseudouridine, methylated nucleosides and bases, and beta-aminoisobutyric acid were found, indicating an increased tRNA turnover rate for the hepatoma tRNA. Methyltransferase activity for the hepatoma monkeys were increased compared to normals; however, large variations in individual methylase activities were found with the hepatoma monkeys having greater thymine, 7-methylguanine and less N2, N2-dimethylguanine activity than the normals. These results, along with the increased excretion levels of the hepatoma monkeys, point to aberrant methylation of the tRNA while the tRNA composition indicates increased tRNA turnover. inary re